Surface-anesthetizing medical appliance

ABSTRACT

Medical devices, endotracheal tubes, having on outside a solid layer comprised of surface-effective anesthetic and solid substance physically securing the anesthetic. The outer surface of the layer has a prolonged anesthetizing effect. Semipermeable flexible adhesive film and semipermeable sheet film across which the anesthetic travels are specifically shown.

United States Patent Richard R. Jackson 8 Trinity Road, Marblehead,Mass. 01947 803,7 17

Mar. 3, 1969 Oct. 5, 1971 lnventor Appl. No. Filed PatentedSURFACE-ANESTHETIZING MEDICAL APPLIANCE 15 Claims, 9 Drawing Figs.

U.S. Cl 128/351, 128/260, 128/272 Int. Cl A6lm 25/00, A61m 31/00, A6lj1/00 Field of Search 128/260, 262, 265, 272, 35]; 424/16, 18, 19, 22

References Cited UNITED STATES PATENTS 10/1967 Jackson 2,803,582 8/1957Cherney 424/19 3,363,624 l/1968 Fishman 128/260 X 3,363,629 1/1968 Kuhn128/351 3,375,828 4/1968 Sheridan 128/351 FOREIGN PATENTS 998,794 7/1965Great Britain 3/1 215,350 10/1909 Germany 128/3 PrimaryExaminer-Channing L. Pace Attorney.lohn Noel Williams ABSTRACT: Medicaldevices, endotracheal tubes, having on outside a solid layer comprisedof surface-effective anesthetic and solid substance physically securingthe anesthetic. The outer surface of the layer has a prolongedanesthetizing effect. semipermeable flexible adhesive film andsemipermeable sheet film across which the anesthetic travels arespecifically shown.

PATENTEDncT 51911 1610247 FiG. 2

Illllllllllllllllllllllllll 5 IO I5 20 25 NUMBING EFFECTSURFACE-ANESTI'IETIZING MEDICAL APPLIANCE This invention relatesgenerally to medical appliances and specifically to endotracheal tubes.

During surgical procedures the depth of general anesthetization is oftendetermined by the need to block the response of the patient to theendotracheal tube that is present in his trachea. In other words thetendency for the patient to buck (tightening of the stomach muscles andtendency of the unconscious patient to sit up) in response to theendotracheal tube is greater that the patients response to the pain atthe site of the incision or the need for maintaining a state of amnesia.This particularly so is cases where administration of muscle relaxantsis inadvisable.

Since it is desirable to maintain body functions as close as possible tonormal during surgery, and since these functions are progressivelyaffected with deeper levels of anesthetization, it has long been desiredto reduce the patients reaction to endotracheal tube throughout thesurgical procedure. Prior tracheal anesthetizing measures areobjectionable for various reasons, e.g. being effective only for shortperiods requiring repeated dosage, or being complicated and introducingnew steps or conditions in the procedure of handling the patient.

It is also desirable to remove from the awakening and fully awakepatient the gag and coughing reflexes caused by the presence of theendotracheal tube. This permits the tube to be tolerated and remain inplace in the awake patient, enabling continued support of respiration bymeans of the endotracheal tube and respirator. Likewise it permitsrespiratory support to be administered immediately should this suddenlybecome necessary. The endotracheal tube also gives better assuranceagainst blockage of the airway by tongue or tissues than do other airwaydevices.

More generally it has long been desirable to provide means fordecreasing sensations caused by medical tubes and similar appliancesresiding in mucous passages of patients over periods in the range of lto 20 hours in a manner requiring no change in the appearance of thetubes or the steps required in their administration.

The objects of the present invention are to meet these various needs ina simple and practical way.

The invention employs an endotracheal or other medical tube which may beof conventional construction in being comprised of a flexible materialsuch as latex rubber or polyvinyl chloride of a thickness sufficient toensure that the fluid passage will not be closed by the flexing actionattendant to the entubation and use of the tube. The tube may includeone or more cuffs in the form of extensible balloons or in the form oflarge, highly flexible floppy cuffs formed of thin film material.Featured therewith is a solid layer or coating having a relatively thineffective thickness and comprised of surface effective anesthetic andsolid substance physically securing the anesthetic. The outer surface ofthis layer has a nontoxic (i.e. within nonharmful dosage limits) surfaceanesthetizing characteristic extending over a period of at least 1 hour,preferably over periods of or hours. Advantageously the initial level ofanesthetic availability is relatively high to achieve quick onset ofsurface anesthetization.

The invention also features a semipermeable membrane or securingmaterial disposed between the surface effective anesthetic in the solidstate and the body tissue, the anesthetic being progressivelytransported thereacross.

The invention also features as the effective layer a matrix formed by anadhesive substance containing a dispersion of solid aggregates orcrystals of surface-effective anesthetic, the substance having adiffusion characteristic for body fluids and for body fluids in whichare dissolved minor quantities of the anesthetic from the matrix.

The invention also features such a matrix layer and layers of othermakeups as integral with tubes and their flexible cuffs, and also aspart of flexible and distensible sleeves applied to preexisting tube andcuff assemblies.

These and other objects and features will be revealed in the followingdescription of preferred embodiments taken in conjunction with thedrawings wherein:

FIG. 1 is a side view partly in cross section and partly diagrammatic,of an endotracheal tube engaging tissue of a patient;

FIG. 2 is a diagrammatic representation of the availability curve of atypical device according to the invention;

FIGS. 3 and 4 are magnified cross sections taken on lines 33 and 4-4 ofFIG. 1, respectively;

FIG. 4a is a greatly magnified view, partly diagrammatic, of a portionof FIG. 4;

FIG. 5 is a perspective view, partly cut away of a sleeve memberaccording to the invention;

FIG. 6 and 7 are views of an endotracheal tube with which the sleeve ofFIG. 5 is combined;

FIG. 8 is a cross-sectioned view of a tube having a wrapping of adiffusion membrane, securing in the inside a deposit of solidanesthetic.

Referring to FIG. 1 an endotracheal tube 10 has'a conventional airpassage 12, an angular-cut distal end 14, a proximal end provided with aconnector for the anesthetic machine, respirator or oxygen line, and aninflatable cuff 20 together with an inflating lumen.

The particular tube shown is made of plastic such as polyvinyl chlorideof a wall thickness 1, of approximately one sixteenth inch. The cuff isconstructed of any suitable flexible film such as extremely thin latexe.g. of less than 0.002 inch thickness and is of a diametersubstantially larger than the trachea, e.g. being 1% inch diameter incomparison with a trachea of inch diameter. Such floppy cuffs aredisclosed in my copending patent applications Ser. Nos. 427,60l and719,994, and require very low pressure to inflate, thus effectivelycombatting the necrosis problem. Such cuffs flex to the shape shown whenthe lung pressure exceeds atmospheric pressure.

Combined with this device, on the exterior surfaces exposed to thetissue of the patient, is a layer 26 comprised on surface effectiveanesthetic and bonding material physically securing the anesthetic inplace.

The layer 26 has the characteristic of presenting at its outer surface,to tissue 28 in contact therewith, surface-effective anesthetization ofnontoxic levels extending over a period of at least 1 hour, preferablyover periods of ID or 20 hours, in accordance with the curve of FIG. 2which will be discussed further below.

In this preferred embodiment the layer comprises an elastomeric adhesivecoating applied to the outer surfaces of a previously formedendotracheal tube and cuff assembly.

In the preferred embodiment of FIG. 5 there is shown a distensiblesleeve member 30 formed of resilient material which is supplied in arolled-up shape.

On its outer surface is a layer 32 similar to layer 26 of the precedingfigures, of such flexibility and resiliency to remain coherent when thetube is convoluted in the roll 30a.

FIGS. 6 and 7 show an endotracheal tube 36 with two cuffs 38, 40 andcorresponding inflation lumens 42. 44. In FIG. 6 the distensible sleeveis shown partly applied to endotracheal tube 3, the two dotted linepositions showing progressive positions during application. In FIG. 7the sleeve is shown fully applied, with the distal cuff 40 inflated,that portion of the sleeve distending therewith and exposing its outersurface to scaling contact with the tracheal wall.

FIG. 8 shows a section of bendable tube 50 to which has been attached afilm wrapping 52 upon the inside surface of which is deposited solidanesthetic particles diffusable through the film upon wetting theoutside by secretions.

EXAMPLE I A conventional endotracheal tube with a balloon cuff similarto one of the cuffs of FIG. 7 was coated on surfaces exposed to mucoustissue with medical grade silicone adhesive containing a dispersion ofsolid particles of a surface effective anesthetic. In preparation, aquantity of tetracaine anesthetic in solid particle form (Pontocaine,"Winthrop Drug Company), was ground by a mortar and pestle until a powderof solid particles was obtained. The particles were greenish-blue incolor. 20 milligrams of the powder were mixed with 1 cc. of medicalgrade silicone adhesive (Vivosil" medical adhesive Silicone-Type A,Becton, Dickinson and Company). The adhesive was water-white in color, anonflowing soft paste. The adhesive with the 2 percent concentration ofdispersed anesthetic particles had a uniform greensh-blue cast. Theprepared quantity (i.e. 20 mg. of tetracaine) was required to providethe layer (26, FIG. I) over the tube and cuff. The coating was allowedto cure at humidity conditions in excess of 20 percent at 77 F.,penetration of the atmospheric water through the silicone adhesivecausing its setup. The resulting layer was estimated to be between a0.003 and 0.005 inch thickness, and provided a shiny, smooth surface. Inthe cured state the layer appeared clear, however under closeexamination the anesthetic particles can be observed (particles did notdissolve in the adhesive). The layer was flexible with the underlyingendotracheal tube and cuff, the layer remaining coherent upon normalbending of the tube and distension of the cuff.

The thus-prepared endotracheal tube was'administered to an age 45female, gall bladder excision, under a normal level of generalanesthetic. Three hours after the operation began the patient awoke inthe recovery room and looked around, with endotracheal tube in place.There were no coughing or gaging reflexes, swallowing being the onlyreaction of the patient even when the tube was jiggled by the attendingphysician. When asked if she felt pain she shook her head no. After thepatient was awake 1 hour the endotracheal tube was removed, with nospasm or coughing observed during removal, indicating anesthetization ofthe upper airway as well as the tracheal tissue in contact with thetube.

An endotracheal tube of identical construction was soaked in water for24 hours, after which anesthetic particles could still be seen in thelayer. After a total soaking of 72 hours the physician placed the tubein his mouth and was able to detect numbing on the tip of his tongue,after minute exposure. Prior to soaking, numbing of his tongue wasdetected with shorter exposure.

In other procedures in which the patients recovered from anesthesia insubstantially less than 4 hours, the patients tolerated the endotrachealtubes well, but moderate coughing occurred during initial recovery.

EXAMPLE 2 A dispersion of tetracaine particles and silicone adhesive wasprepared as in Example 1, with 30 mg. tetracaine per cc. of adhesive (3percent concentration). This mixture was diluted by 3 cc. of ether andthe resulting dilute suspension was painted on the endotracheal tube intwo coatings to form layer 26 of FIG. 1. The overall thickness of thelayer was estimated to be between 0.002 and 0.004 inch in thickness.When setup the layer presented a smooth, shiny surface.

This tube was placed in a patient having glaucoma, undergoinglridentasis. Twenty minutes after anesthetization the patient awoke withthe tube in place and with no reaction.

A similar tube was employed in a patient undergoing gall bladder removal(cholecystectomy). The patient was maintained on a respirator (assistedbreathing) for 4 hours after awakening. After cessation of therespirator the tube was left in the awake patient for 1 hour. After thisperiod the tube was jiggled by the attending physician with no reactionwhatever by the patient.

Similar tubes were employed in procedures of short duration(e.g. acarotid arteriogram procedure) and in longer circumstances (e.g. thetube was maintained in an unanesthetized patient for 18 hours while hisbreathing was assisted by a respirator). In these cases the tubes werewelltolerated in the awakening patient.

EXAMPLE 3 A sleeve of distensible latex rubber of 4 inch length, inchinternal diameter, was coated on its exterior with a mixture of siliconeadhesive containing a 2 percent concentration of tetracaine particlesslightly diluted with ether. After solidification of the adhesive layerthe physician, by applying the outer surface of the the to his tongueand lips, detected numbness within 2 minutes.

The sleeve was slipped over an endotracheal tube having s single ballooncuff, using liquid soap as lubricant. The tube was inserted and the cuffinflated with air, distending he sleeve in the manner ofcuff40 in FIG.7.

The operation, surgery on the abdominal wall of an age 83 female, wasconducted without muscle relaxants with an unusually light level ofanesthesia:

4 liters per minute nitrous oxide 2 liters per minute oxygen 1%halothane (Fluothane, Ayerst Co.).

EXAMPLE 4 An endotracheal tube cuff was formed by a 19/16 inch diameter,approximately 0.002 inch wall thickness, cellophane tube (WeckSterilizing tubing," Edward Weck & Co., division of Sterling PrecisionCorp.) applied over an endotracheal tube, and tied to the endotrachealtube at opposite ends spaced approximately 2 inches apart. An inflatinglumen was connected to the cuff volume. The cuff was filled with 10 cc.of a 2 percent solution (water base) lidocaine hydrochloridesurface-effective anesthetic (xylocaine," Astra PharamaceuticalProducts). The cuff was exposed to air for 4 days until the liquid haddried within the cuff, forming a deposit of 200 milligrams solidanesthetic on the inner surfaces of the cuff assembly. The deposit wasnot observable through the cellophane and was not friable. The exteriorof the cuff was moistened with a slight amount of saline solution, torestore the flexibility of the cellophane, and the endotracheal tube wasinserted into a patient and the cuff was inflated by introduction of airthrough the lumen. The patient awoke after 4 hours. The tube was jiggledin the trachea of the conscious patient without causing cough.

The procedure was repeated with a number of patients with same results.

EXAMPLE 5 A loose wrapping was formed using the cellophane tubing ofexample 4 along a portion of the endotracheal tube proximal to theinflatable cuff. 20 cc. of 2 percent lidocaine hydrochloride, waterbase, was dried within this wrapping forming a coating on the innersurface of the cellophane. The cellophane wrapping was collapsed uponthe endotracheal tube in irregular folds.

The endotracheal tube was inserted with the wrapping located proximal ofthe trachea. The attending physician observed that the gas reflex of theawake patient was obtunded for 8 hours.

Referring now to FIG. 3, a magnified cross-sectional view along line 3-3of FIG. 1, mucous tissue 29 lying proximal of the trachea contacts theouter surface of the layer 26. It has been observed that the gag reflexcaused by such contact is obtunded over an extended period by anestheticpassing from the layer 26. The physical securement of the anestheticprevents its being washed away by normal secretions, indeed in importantinstances it is believed that the secretions play an important part inprogressive transport of the surface-effective anesthetic to the tissue.It should be observed that the effective thickness of the layer t, isonly a small fraction of the remaining thickness of the tube wall t,which defines the passage in a manner which permits bending withoutclosingoff the passage.

Referring to FIG. 4, a magnified view along line 44 of FIG. 1, it isseen that the cut? 20, inflated by air 24, seals against the tissue oftrachea, with direct contact between layer 26 and the tracheal tissue.It has been observed that the coughing and bucking reflexes caused bysuch contact are obtunded over an extended period by anesthetic passingfrom the layer 26. Here again the physical securing of the anestheticprevents its being washed away by normal secretions, the secretions inimportant instances believed to be effective in causing progressivetransport of the anesthetic to the tissue.

The relationship of the effective thickness 1, of the layer and theremaining thickness t of the cuff corresponds to cuffs of the balloontype such as are shown in FIG. 6. As was shown above in example 4,however, where thinner flexible cuffs are employed, the wall thicknessof the cuff can comprise the layer in or to which the anesthetic issecured.

Referring to FIG. 4a, a diagrammatic highly magnified cross-sectionalview of the layer 24 in action, there are shown three anestheticparticles a, b and 0. Particle a is spaced distance I, away from thetissue, corresponding with the distance all of the anesthetic was spacedfrom the tissue in examples 4 and 5, and some of the anesthetic in theother examples.

Secretions travel from the tissue 28 through the layer to particle a andupon dissolving slightly, the anesthetic passes through thesemipermeable thickness to tissue 28.

Advantageously some of the anesthetic is positioned closer to theeffective surface, as for instance particles b and c. Particle c, nearor at the surface, can, with proper selection of the anesthetic, provideimmediate onset of anesthetization, or, if relatively insoluble in water(and therefore insoluble in the secretions) many maintainanesthetization for a substantial period. Particle b enables anintermediate condition to be achieved.

it will be seen that choice of the particular components of the layerwill depend upon the desired characteristics of the device. Usingmaterials available currently, it is most preferred to employ a solidcoating in which the anesthetic is distributed from the outer surface toa depth of at least 0.001 inch as illustrated by each of the tinyparticles a, b and c, with the inner particles masked with semipermeablematerial as in the foregoing examples. By this means rapid onset isachieved, but also the layer (being of semipermeable material orrendered so) has an impeding effect that ensures the availability of theanesthetic over an extended period.

It is preferred to employ silicone adhesive diluted with ether or thelike, dilution not only enabling smoother and thinner coatings but alsobelieved to increase the permeability of the coating to such anestheticsas tetracaine which, being water and not oil soluble, has very lowsolubility in silicone.

Suitable semipermeable substances presently known to the inventor, inaddition to silicone adhesive and sheet films, are regenerated cellulose(cellophane) and cellulose nitrate. The cellulose thickness in importantinstances is less than 0.005 inch.

Whatever the type of construction of the layer chosen, a requirement isthat the outer surface of the layer have a nontoxic surfaceanesthetizing characteristic extending over a period of at least 1 hourand preferably over periods of or 20 hours. FIG. 2 is a curve of thecharacteristic of a typically acceptable embodiment. The horizontal linedenotes the threshold of anesthetizing effectiveness, established by adetectable numbness of the tongue after contact with the surface of thelayer for 5 minutes. For the examples above the nontoxicity of thequantities of anesthetic is shown by the fact that accepted priorpractice has been to apply to the tracheal tissue at a single instantequivalent or greater quantities of the anesthetic by means of spray orointment (with however only short lasting affect). No toxic reactionswere observed for the examples described above.

The required anesthetizing characteristic can be achieved through simpletests with variation of the constituents and their relationship to oneanother. For instance, for the preferred embodiment variable parametersinclude the nature of the semipermeable membrane or adhesive material,the

chemical nature of the anesthetic with regard to such factors assolubility in water and secretions, the thickness of the membrane andthe distribution and concentration of the dry anesthetic.

Numerous variations within the spirit and scope of the claims will occurto those skilled in the art.

What is claimed is: t

l. A medical tracheal tube constructed for insertion into a body passagefor prolonged exposure to mucous tissue of the patient, and having onits outside a solid layer comprised of solid surface effectiveanesthetic and solid substance physically securing the anesthetic withrespect to the tube, both said anesthetic and said substance being solidat body temperature, the outer surface of said layer having a nontoxicsurface anesthetizing characteristic extending over a period of at least1 hour.

2. The tracheal tube of claim 1 wherein said solid substance is at leastin part semipermeable to secretions of mucous tissue and to solutions ofsaid anesthetic in said secretions whereby said anesthetic can begradually dissolved and flow in solution into contact with some mucoustissue over a prolonged period of time.

3. The tracheal tube of claim 2 wherein said solid substance comprisesan adhesive forming a coating on said tube with anesthetic distributedtherethrough.

4. The tracheal tube of claim 3 wherein said solid substance comprisessemipermeable silicone adhesive and said anesthetic is present in saidadhesive in the form of solid particles.

5. The tracheal tube of claim 2 wherein as least part of said solidanesthetic is spaced from the outer surface of said layer by saidsemipermeable solid substance.

6. The tracheal tube of claim 1 wherein said tube is formed of resilientmaterial, adapted to bend during insertion into the patient, and saidlayer is flexible and adapted to conform to said medical tube.

7. The tracheal tube of claim 6 wherein said layer comprises anelastomeric substance integrally united to said tube.

8. In a tracheal tube for introducing air into the lungs of a patient,said tube having means on its exterior surface for applying surfaceeffective anesthetic to the tissue of the trachea by means of diffusionthrough a thickness of material having a diffusion characteristic, theimprovement wherein said exterior surface is defined by film exposed forcontact with body tissue to be anesthetized, said film carryingsubstantially dry surface-effective anesthetic spaced inwardly from saidexterior surface, said film material and said surface-effectiveanesthetic being solid at body temperature and semipermeable by a liquidcompatible with said body tissue to mobilize said anesthetic to diffuseto said exterior surface.

9. The tracheal tube of claim 8 including an inflatable cuff securedadjacent the distal end of said tube, wherein said cuff is formed bysaid film material, and at least one air passage adapted to introduceair into said cuff to cause said cuff to seal against tracheal tissue.

10. The tracheal tube of claim 9 wherein said film material and saidsurface effective anesthetic are semipermeable by water.

11. The tracheal tube of claim 10 wherein said cuff is comprised ofsemipermeable cellophane of a thickness less than 0.005 inch and saidsurface-effective anesthetic is in the form of a deposit adhered to theinner surface of said cuff, whereby said anesthetic can diffuse throughsaid cuff to the tracheal tissue.

12. A means for applying surface effective anesthetic by diffusionthrough a thickness of material having a diffusion characteristicwherein the material comprises a film having a surface exposed forcontact with body tissue to be anesthetized, the film carryingsubstantially dry surface-effective anesthetic spaced inwardly from saidsurface, said film material being permeable to and said surfaceanesthetic being dissolvable by a liquid compatible with said bodytissue to mobilize said anesthetic to diffuse to said surface.

posite to said surface that is exposed for contact with body tissue.

15. The means of claim 12 wherein said surface-effective anesthetic isdispersed through the mass of said film.

1. A medical tracheal tube constructed for insertion into a body passagefor prolonged exposure to mucous tissue of the patient, and having onits outside a solid layer comprised of solid surface effectiveanesthetic and solid substance physically securing the anesthetic withrespect to the tube, both said anesthetic and said substance being solidat body temperature, the outer surface of said layer having a nontoxicsurface anesthetizing characteristic extending over a period of at least1 hour.
 2. The tracheal tube of claim 1 wherein said solid substance isat least in part semipermeable to secretions of mucous tissue and tosolutions of said anesthetic in said secretions whereby said anestheticcan be gradually dissolved and flow in solution into contact with somemucous tissue over a prolonged period of time.
 3. The tracheal tube ofclaim 2 wherein said solid substance comprises an adhesive forming acoating on said tube with anesthetic distributed therethrough.
 4. Thetracheal tube of claim 3 wherein said solid substance comprisessemipermeable silicone adhesive and said anesthetic is present in saidadhesive in the form of solid particles.
 5. The tracheal tube of claim 2wherein as least part of said solid anesthetic is spaced from the outersurface of said layer by said semipermeable solid substance.
 6. Thetracheal tube of claim 1 wherein said tube is formed of resilientmaterial, adapted to bend during insertion into the patient, and saidlayer is flexible and adapted to conform to said medical tube.
 7. Thetracheal tube of claim 6 wherein said layer comprises an elastomericsubstance integrally united to said tube.
 8. In a tracheal tube forintroducing air into the lungs of a patient, said tube having means onits exterior surface for applying surface effective anesthetic to thetissue of the trachea by means of diffusion through a thickness ofmaterial having a diffusion characteristic, the improvement wherein saidexterior surface is defined by film exposed for contact with body tissueto be anesthetized, Said film carrying substantially drysurface-effective anesthetic spaced inwardly from said exterior surface,said film material and said surface-effective anesthetic being solid atbody temperature and semipermeable by a liquid compatible with said bodytissue to mobilize said anesthetic to diffuse to said exterior surface.9. The tracheal tube of claim 8 including an inflatable cuff securedadjacent the distal end of said tube, wherein said cuff is formed bysaid film material, and at least one air passage adapted to introduceair into said cuff to cause said cuff to seal against tracheal tissue.10. The tracheal tube of claim 9 wherein said film material and saidsurface effective anesthetic are semipermeable by water.
 11. Thetracheal tube of claim 10 wherein said cuff is comprised ofsemipermeable cellophane of a thickness less than 0.005 inch and saidsurface-effective anesthetic is in the form of a deposit adhered to theinner surface of said cuff, whereby said anesthetic can diffuse throughsaid cuff to the tracheal tissue.
 12. A means for applying surfaceeffective anesthetic by diffusion through a thickness of material havinga diffusion characteristic wherein the material comprises a film havinga surface exposed for contact with body tissue to be anesthetized, thefilm carrying substantially dry surface-effective anesthetic spacedinwardly from said surface, said film material being permeable to andsaid surface anesthetic being dissolvable by a liquid compatible withsaid body tissue to mobilize said anesthetic to diffuse to said surface.13. The means of claim 12 wherein said film is comprised of materialfrom the group consisting of silicone, cellulose nitrate an regeneratedcellulose.
 14. The means of claim 12 wherein said film is less thanabout 0.005 inch thick and said surface-effective anesthetic is in theform of a deposit adhered to the surface of said film opposite to saidsurface that is exposed for contact with body tissue.
 15. The means ofclaim 12 wherein said surface-effective anesthetic is dispersed throughthe mass of said film.